Intrafollicular Hermaphroditism in the Marine Mussel,Mytilus edulisL.

Summary Histological features of a special case of hermaphroditism in the marine mussel Mytilus edulis are reported. The major part of the gonad of this specimen was taken up by an abnormally large follicle which was ambisexual but predominantly male. A lack of synchronous release of the male gametes was evident within the gonad. One area consisting of abnormally large follicles had already spawned, with some residual spermatozoa and developing oocytes remaining in the lumen, whereas another part was undergoing normal development.